Filter Assembly
At U.S. published application number 20150113924; Mathews et al. wrote in the abstract, “A stackable, portable air filtration unit utilizing a molded plastic central housing, injection-molded plastic inlet and outlet covers and accommodating a high-efficiency particulate air (“HEPA”) filter or other high efficiency particulate filter, a secondary filter and a pre-filter. The unit is versatile and flexible in that different motorized impellers can be used alternatively, depending on the desired specifications.” Mathews et al. also expressed that their portable air filtration unit has a housing with a carrying handle, a sloping control panel and an air exhaust. To the left of the housing are a venturi ring, a high-efficiency filter, high-efficiency filter securing brackets, a secondary filter, a pre-filter and an inlet door. To the right of the housing may be seen a motorized impeller, a motor mount, an outlet cover, a control panel box and a control panel assembly, which includes a control panel. When these components are assembled, the inlet door permits entry of unfiltered air through inlet, which is drawn in and through the pre-filter, the secondary filter and the high-efficiency filter by the motorized impeller. When closed, the inlet door secures the pre-filter and the secondary filters in their appropriate places and seals against housing with a latch and keeper, one side of which is attached to the housing and the other side of which is attached to the inlet door. A pair of hinges on the opposite side affix the door to the housing. This sealing engagement between the inlet door and the housing assures that air drawn into housing must pass through the three filters. This sealing engagement calls for the door, when opened, to have the pre-filter seated in a like-shaped cavity on the inner side of inlet door. This customized cavity inhibits any significant air flow to bypass pre-filter as can happen with some air filtration units. The pre-filter is surrounded by a raised boss, contoured to match the filter side recess in housing, which is generally rectangular and has two tabs extending up and two tabs extending down from the rectangular portion of the raised boss. The housing has a generally rectangular recess with upward facing and downward facing tab-receiving recesses. Opposed pairs of the recesses in housing receive the two ends of the high-efficiency filter securing brackets. The brackets may be sections of square or rectangular cross-section tubing, channel, such as C-shaped, L-shaped or other cross-section channel, or a wide variety of other elongated structures including a metal strap, a rod or a bar stock. The recesses extend into the housing so that the brackets are fully seated in pairs of recesses hold the high-efficiency filter in its intended position in the housing and may be secured, among other ways, by screws, pins, bolts or other fasteners that pass through bracket ends and into housing or into suitable fittings attached to housing such as threaded metal inserts.
As explicitly acknowledged by Mathews et al., its filter assembly requires tools to remove the high-efficiency filter from or attach the filter to the filter assembly. Those tools along with the conventional fasteners are utilized to obtain an air-tight (with the understanding that air-tight permits air to enter into and escape from the filter assembly at designated apertures) and leak-proof environment in the filter assembly. The present invention is directed to avoid the use of tools to change the high efficiency filter in a filter assembly, clean the interior of the filter assembly, and also ensure the air filtration system receives air intended to be filtered through a HEPA air filter in an air-tight, leak-proof environment.
Similarly, Americair, Inc., the assignee of this application, is the manufacturer of its AIRWASH HEPA air filtration system which has a housing. The housing has an air inlet and an air outlet, and within the housing is a fan/motor and a HEPA filtration system. The fan/motor draws air through (a) the air inlet which can have a pre-filter apparatus, (b) a foam pre-filter that removes larger particulates such as dust and dander, (c) a high efficiency particulate removal filter media that is laser tested to remove 99.97% of the particles in the air stream down to a size of 0.3 microns—particles of concern which are normally in this size range include pollen, household dust, cigarette smoke, bacteria, molds, etc.; (d) an inner blanket (which can be like ½ inch) of activated carbon impregnated with non-woven polyester filter material which absorbs additional gaseous contaminants such as odors and toxic fumes; and (e) the air outlet.
Everything defined immediately above is generically a component in the instant invention—(1) a housing having an air inlet and an air outlet, (2) a fan/motor device that pulls or pushes air though the housing and a HEPA air filter, and (3) the HEPA air filter system that cleans the air as described in items (a) to (d) immediately above.
In particular the AIRWASH air filtration system can cleanse up to 1,000 cubic feet of air per minute. The applicant conducted a particulate study that compared the number of particulates in a 15′×30′ room prior to operating its AIRWASH air filtration system (referred to as “Ambient Room”) and after its AIRWASH air filtration system operated for 20 minutes (referred to as “20 min Operating”), wherein the particle reader, identified above, was positioned on a conventional end table in the middle of the room. The results are as follows:
ConditionParticle CountAmbient Room297,40020 min Operating166,400HEPA Filter
Americair Corporation manufactures numerous types of air filtration devices and filters, in particular HEPA air filtration devices and filters. Its HEPA air filtration devices are large, medium and small devices that utilize corresponding sized filters. Its filtration devices, like Mathews et al.'s filtration assembly, require tools to insert and replace HEPA filters. Americair also manufactures a threaded HEPA filter having an EasyTwist brand threaded end cap.
That threaded HEPA filter has a threaded end cap at one end, a HEPA filter section and a second end cap at the other end. The threaded end cap has an aperture, essentially positioned in the center of the threaded end cap, with a wall extending in a direction toward the second end cap. The wall has the threaded area of the threaded end cap.
The threaded area releasably engages with a corresponding threaded protrusion of an air filtration device's bulkhead in or on its air filtration system. In one embodiment, a filter o-ring is positioned around the threaded protrusion, thereby the o-ring creates an air-tight seal between the threaded end cap and the bulkhead when the two components are properly positioned together. That air-tight seal is designed to inhibit air in the air filtration device from bypassing the filter.
The bulkhead, preferably, has an opening within an area defined by or encircling the threaded protrusion. That bulkhead opening directs air into or out of the HEPA air filter and/or the air outlet, depending on the air flow's direction, to obtain the desired air quality after the air passes through the HEPA air filter.
Americair's threaded HEPA air filter has the following characteristics:                Cylindrical Perfect Seal 2-Stage Cartridge (13″ Diameter×16″ Height)        Stage One: ⅛″ Foam Prefilter        Stage Two: Granulated Carbon pellets encased in steel mesh canister (9475 g=10,422,500 m2 adsorption surface area)        Optional Stage Two: 100 sq. ft. Pleated Easy Twist HEPA Cartridge        Optional Stage Three: Granulated Carbon pellets encased in steel mesh canister (1550 g=1,705,000 m2 adsorption surface area)        
In its manuals that describe how to install the threaded HEPA filter in an Amaircare® brand air filtration device, Americair wrote, “With the filters changed or inspected, all 3 filters are ready to be placed back into the unit. Place the HEPA cartridge gently into the unit (if a carbon canister is being used, take care not to let it slide out as it is heavy and could damage the unit.) When the HEPA cartridge is in place, brace the unit, press down and gently turn its clockwise to lock it into place. If too much force is used, the cartridge may be difficult to remove! Replace the HEPA filter access panel. Re-install safety screw(s) into HEPA filter access panel.” Again tools and fasteners are required and should be avoided.